1. Technical Field
This disclosure relates generally to a turbine engine and, more particularly, to cooling a multi-walled structure of a turbine engine.
2. Background Information
A floating wall combustor for a turbine engine typically includes a bulkhead, an inner combustor wall and an outer combustor wall. The bulkhead extends radially between the inner and the outer combustor walls. Each combustor wall includes a shell and a heat shield that defines a respective radial side of a combustion chamber. Cooling cavities extend radially between the heat shield and the shell. These cooling cavities fluidly couple impingement apertures defined in the shell with effusion apertures defined in the heat shield.
During turbine engine operation, the impingement apertures direct cooling air from a plenum adjacent the combustor into the cooling cavities to impingement cool the heat shield. The effusion apertures direct the cooling air from the cooling cavities into the combustion chamber to film cool the heat shield. This cooling air subsequently mixes and reacts with a fuel-air mixture within the combustion chamber, thereby leaning out the fuel-air mixture in both an upstream fuel-rich primary zone and a downstream fuel-lean secondary zone. The primary zone of the combustion chamber is located between the bulkhead and the secondary zone, which is generally axially aligned with quench apertures in the combustor walls.
In an effort to increase turbine engine efficiency and power, temperature within the combustion chamber may be increased. However, increasing the temperature in the primary zone with a relatively lean fuel-air mixture may also increase NOx, CO and unburned hydrocarbon (UHC) emissions.
There is a need in the art for an improved turbine engine combustor.